It is often desired when watching streaming video of an event such as a televised football match, to navigate backwards to a specific segment of the streaming video in order to re-view a significant occurrence, such as, for example, the scoring of a goal, or a contentious decision made by a referee.
Unfortunately, existing practice for transmitting streaming video (especially over the Internet) creates a condition that hampers, or renders unfeasible, execution of a backwards navigating operation to reach the specific segment. This condition arises from the fact that existing streaming video transmission practice is directed at conserving transmission bandwidth by using a sequence of differentially compressed image frames interspersed with, what is known in the industry, as key frames (statically compressed frames that are independent of other frames). Differentially compressed image frames do not carry enough information for the video system to navigate backwards to the specific segment of the streaming video, or to switch from a first video stream to a second video stream, without the video system having to obtain access to other image frames from which the differentially compressed frame has been derived.
However, key frames do provide enough information that can be used for various purposes, including identification of one or more specific segments in a video stream, or to switch from a first video stream to a second video stream. Consequently, existing streaming video systems, upon receiving a request (via a mouse click, for example), wait for the next key frame, and use this next key frame to locate the specific segment or to execute a video stream switching operation. This waiting period introduces a noticeable amount of delay. Such a delay is highly undesirable, especially when a viewer is watching a fast-paced event such as a football match.
In addition to introducing this undesirable delay, existing streaming video systems also fail to provide a fast, convenient and user-friendly way for a viewer to initiate a request for a backwards navigating operation. Typically, in existing streaming video systems, such a request is initiated by a viewer carrying out a selection upon a text menu displayed on a viewing screen, followed by using a picture-in-picture configuration for swapping a live view displayed on the main portion of a display screen with a view displayed in a small window. The method of using such a picture-in-picture configuration adds an additional delay to that already introduced by the above-described wait for the next key frame, besides having other issues.